AppColl stores your session's browsing history, which allows you to return to any previous point in your session with a single click.

In the upper-left corner of your screen is a small blue downward-facing arrow. Click the arrow to display a popup of your browsing history. Click any of the rows in the popup window to jump to that page. The blue arrow will not appear until you have visited more than one page in a session. 

Note: Session history is only saved for the current session. After you log out, the session history resets.